There has been a need in the art for a spray nozzle, to be used in typical evaporative heat exchangers, which provides a generally circular and umbrella-like spray pattern over a wide range of fluid pressures. Use of such nozzles makes it possible to maintain the heat exchanger fully wetted so as to maximize heat transfer and/or minimize scale formation.
Further, in typical evaporate heat exchangers it has been customary to provide several liquid carrying headers located in superposed relation spanning either a bank of tubes carrying a fluid to be condensed and/or cooled or spanning cooling tower fill. A plurality of smaller tubes or branches extend laterally from the headers, with each branch containing one or more nozzles which emit spray patterns which impinge on the fluid carrying tubes or fill. In this prior application, fine sprays have been used because of the relatively large ratio of drop surface area to drop volume which results in optimum evaporative cooling efficiency.
Accordingly, it had been necessary to provide multiple arrays of such small fine spray nozzles. The number of nozzles in a typical prior art installation may be on the order of one or more nozzles per square foot of plan area of the heat exchanger. These are arranged in a generally uniform spacing to obtain an overall rectangular spray pattern within the usually rectangular plan area of such heat exchange units. A great deal of mist is generated by such sprays and much of this impinges on the walls of the unit or is carried upwardly by rising convention air currents requiring the use of complex drift eliminators to avoid loss of cooling water.
In another typical prior art installation as shown in U.S. Pat. No. 4,058,262 there is shown use of spray nozzles wherein each nozzle forms with another a cooperative pair to form a generally rectangular spray pattern in a liquid heat exchanger or evaporation system. The nozzles shown in this patent must work one in conjunction with another and only emanate individually a generally semicircular spray pattern. The fact that the nozzles in this patent do not emit a circular spray pattern leads one to use many more nozzles than are needed in the subject invention.
Further, the sprays from the nozzles shown in U.S. Pat. No. 4,058,262 do not interact in a manner such that the spray fluid is uniformly distributed over the surface area beneath said nozzles.
Also, there is provided in U.S. Pat. No. 3,617,056 a type of nozzle to be used mainly in gravity feed operations, said nozzle having a specifically constructed bottom plate to distribute the fluid in a desired pattern.
Applicant has found an improved spray nozzle which provides sufficient fluid flow over a wide range of fluid pressures and has provided a nozzle which can be economically manufactured. Further, applicant has found an improved spray nozzle which provides an umbrella-type spray pattern that interacts with the spray patterns from adjacent nozzles, in both length and width directions, to uniformly distribute the spray fluid over the surface area beneath the nozzles, while at the same time requiring a minimum number of nozzles.
It is an object of this invention to provide an improved spray nozzle to be used with headers wherein liquid to be distributed is under pressure which emits a circular 360.degree. uniform umbrella-like spray pattern over a wide range of said liquid pressures.
It is a further object of this invention to provide a nozzle of a relatively simple design that is economically feasible to manufacture and which not only distributes the liquid in a circular 360.degree. spray pattern but distributes said liquid uniformly over the 360.degree. pattern for a wide range of pressure of said liquid in said header.
A still further object of this invention is to provide an improved spray nozzle which results in the use of less nozzles than previous spray systems.
The above and other objects and advantages will become apparent from the following description and from the accompanying drawings and will be recognized by those skilled in the art.